1. Field of the Invention
The present invention relates generally to commercial food display cases of the type commonly found in supermarkets and similar establishments. In a more particular sense, the application is directed towards cases of the type described in which the front of the case is closed by a display window and access to the case is normally made through rear doors. Cases of this type are in widespread use for marketing of service meats, cheeses, prepared foods, and other products that must be sliced or otherwise prepared according to the retail food customer, as well as for marketing other products such as delicatessen items and fresh food.
More particularly, the field of the invention is directed towards a method of manufacturing a display case which may be refrigerated, heated, or xe2x80x9cdryxe2x80x9d, i.e., lacking any temperature regulating apparatuses.
The display cases of the type described above are widely used within the retail food industry. When the cases are designed for either hot or cold food displays, it is desirable that the display cases be provided with good thermal insulation properties. Accordingly, it is necessary to provide a central food display compartment which is surrounded as completely as possible by a thermal barrier including insulation along the non-glass walled surfaces of the display case.
While it is known in the art to provide standard insulation materials within the wall spaces which are opposite the display enclosure, there remains room for variation and improvements in the manufacturing process which simplifies the manufacturing process and enables a more efficiently constructed display case which makes use of less labor-intensive methods.
Typically, the structural walls, top, and bottom of a display case of the present type make use of metal panels which are fastened together with sheet metal screws or other separate fasteners. As the panels are constructed, insulation in a form of fiberglass batts or sheets or foam is placed within the panels to provide thermal insulation for the non-glass components of the display case. While the use of in place foamed insulation is known within the art, the methods of constructing a display case having foamed in place urethane insulation have changed little. The conventional teaching provides for the of construction of a rigid metal display unit which then undergoes a foaming step between the inner and outer frame walls surrounding the food enclosure.
However, there has been no suggestion in the art which takes advantage of the adhesive and rigidity properties of a single unitary network of cured foam which allows a construction method which can eliminate certain interconnective steps and attachment parts typically used to construct the display case. As a result, the components may be redesigned to have simple overlapping flanges and avoid the need for special tooling or parts. Accordingly, there remains room for improvement and variation within the art of display cases and methods of their construction.
The present invention provides an improved method of constructing a food display case. The construction techniques make use of a crimping tool which stitches together overlapping metal flange portions of the component display panel. The resulting stitched seams permit the rapid assembly of the non-glass structural components. The resulting display frame, while self-supporting, lacks overall rigidity and possesses a great deal of play and flexibility. In situ foaming of the spaces between the interior and exterior display walls, floor panels, and top panels, provides a rigid spaced connection between the adjacent panels and provides for the overall rigidity and increased strength of the resulting display case.
As a result of the high strength bond provided between the foamed walls and panels, traditional and labor-intensive fasteners are not required to interconnect the panels. Rather, a rapid, less permanent connection is made followed by the in situ foaming of the panels. Once the foamed has cured, the insulating foam provides strength and support to the display structure.